I can't compress front caliper back in

Caliper pistons and bores are these funny animals with such close tolerances that, if the piston came far enough to be out of the bore, it will not go back in unless you are gently working it back in perfectly straight. Set the C clamp aside because force won't help, you can just end up getting the piston cocked and distort things. Open the bleed screw so the fluid has a place to go, and with your fingers just experiment with finding where "perfectly straight" is until the piston slips back in. You should be able to press it at least part way back in with just your fingers. If it gets harder to push the rest of the way in, you can bring back the C clamp, but only after you know the piston is really in the bore and really will slide.

Then bleed the brakes after reassembly.

-Chap

 

I agree with brother ChapmanF, The piston on our cars is really delicate and once completely out, will not go back in unless it is aligned right. Take your time, use your hands, and should find success. I have read a lot about replacing the pads in here and they all said "be careful and delicate". Good luck and let us know how it goes.